1. Field of the Invention
The invention relates to a headband apparatus for an optical instrument comprising a headband and a bow on which said optical instrument is mounted, said bow being mounted with both ends thereof at a middle region of said headband for swiveling about a swivel axis between a working position and a rest position.
2. Description of the Background Art
Such a headband apparatus known from U.S. Pat. No. 4,681,413 comprises an elastic headband surrounding the forehead and back of the head, and a crown band permanently connected thereto. The headband and the crown band can be adapted to the size and shape of the wearer's head with the aid of adjusting apparatuses. A bow is swivelably supported with its two ends in the middle side region of the headband. A binocular ophthalmoscope is fastened on the front side of the bow. The bow can be swiveled upward from a substantially horizontal working position, in which the ophthalmoscope is located in front of an examiner's eye into a rest position in which the ophthalmoscope is brought completely out of the examiner's field of view. Provided at one of the two swivel axes for the purpose of swiveling the bow is a latching device with two stops into which the bow latches in the working position or the rest position. The latching device has an operating element after the activation of which the bow can be unlocked and moved into the appropriate position. The latching device is permanently mounted on the swivel axis of the bow. This means that each examiner, whether a left- or right-hander must use the latching device, arranged on the side of the headband, in order to set the bow. If the latching device is arranged for right-handers, as is normally the case, this constitutes a substantial impairment of the operating comfort for a left-hander. For this reason, the manufacturer finds it necessary to make separate headband apparatuses available both for left-handers and right-handers, thus giving rise to substantial outlay on development and production. Moreover, the known headband apparatus does not provide any additional devices for fastening supplementary apparatuses or units. Finally, the bow is held in the working position at only one end by the latching device. Consequently, the bow is inclined downward in the direction of the other end because of the weight of the ophthalmoscope.